SAE J661_202110 Brake Lining Quality Test Procedure 

The purpose of this SAE Recommended Practice is to establish a uniform laboratory procedure for securing and reporting the friction and wear characteristics of brake linings. The performance data obtained can be used for in-plant quality control by brake lining manufacturers and for the quality assessment of incoming shipments by the purchasers of brake linings.

A typical commercial machine used to prepare for this test procedure, known as a friction material testing machine. The friction material testing machine should be equipped with appropriate devices:
One. Measure the drum temperature
b. Heating drum
c. Control the heating rate of the drum
d. Cool the drum from the back only
e. Control the cooling rate of the drum
f. Measure friction
g. Measure the drum speed
Methods for measuring the thickness and mass of the specimen should be provided.
The temperature measurement device should include a welded thermocouple, a coin silver slip ring, a silver graphite brush, and an indicator and/or recorder with a high input impedance.
The drum heating device should be adjusted and left as it was during the test, with the drum rotating at 417 r/min and the cooling air turned on from 149 °C (300 °F) to 93 °C (200 °C). It is then cooled to 82 °C (180 °F) with the cooling air turned off. Turn on the heater at 82 °C (180 °F) and start the timer. Heat for 10 minutes. The drum temperature should be maintained between 221 °C ± 14 °C (430 °F ± 25 °F) for 10 minutes.
The drum cooling unit should be adjusted so that the drum rotates at a speed of 417 r/min and after the drum has been heated to 371 °C (700 °F) using the heater element, the heater is turned off and the cooling air is turned on. Cool to 343 °C (650 °F) and start timer. Cool for 10 minutes. The drum temperature should be 93 °C ± 14 °C (200 °F ± 25 °F) for 10 minutes.
The temperature measurement system should have a full-scale accuracy of ±2%.

4 Test Conditions—Actual tests for performance shall be started when preparations have been completed in

accordance with Section 5.

4.1 Conduct of Test—All testing shall proceed without interruption.

4.2 Drum Speeds—All drum speeds (r/min) are based on a nominal 279.4 mm (11.0 in) diameter drum with load applied to the specimen.